"Night"

[Joshrk22]

The time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time.

"Night" means the time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time.

Can anyone tell me when civil twilight is? The AIM mentions something about 6 degrees with the sun or something, but who is going to get their protractor out to measure this? My private pilot study prep manual doesn't even tell me. Can someone enlighten me? Thanks.

 

[aucfi]

According to the U.S. Naval Observatory, civil twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 6 degrees below the horizon. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities. Complete darkness, however, ends sometime prior to the beginning of morning civil twilight and begins sometime after the end of evening civil twilight. [FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]Sunrise and sunset conventionally refer to the times when the upper edge of the disk of the Sun is on the horizon, considered unobstructed relative to the location of interest. Atmospheric conditions are assumed to be average, and the location is in a level region on the Earth's surface.[/FONT]

 

[midlifeflyer]

Can anyone tell me when civil twilight is? The AIM mentions something about 6 degrees with the sun or something, but who is going to get their protractor out to measure this?

These guys will:

http://aa.usno.navy.mil/data/docs/RS_OneDay.html

 

[satpak77]

dude "night time" is when its night out or "not daytime, sunrise, nor sunset"

don't make it hard than it really is

 

[A Squared]

dude "night time" is when its night out or "not daytime, sunrise, nor sunset"

don't make it hard than it really is

Ummm, duuuuude, no it is not. Night time is not everything which is "not day, sunrise nor sunset".

There actually *is* a specific legal definition of night, and your definition is wrong. You're not making it easier, you/re just making it "wronger"

 

[UndauntedFlyer]

We turn on the position lights from sunset to sunrise. We log night landings from one hour after sunset to one hour before sunrise. When is the official night used for anything? I guess it would be for logging night flight but not night landings for currency. Is that right? I really don't know. Any thoughts on this?


Also I have an official copy of the "American Air Almanac." It contains the official twilight for the definition of "night."

 

[Daytonaflyer]

Undauntedflyer,
That sounds about right to me. I use a rule of thumb: 30 minutes after official sunset equals "evening civil twilight" for logging night time. Use one hour after sunset for logging night landing currency. The only thing I use "sunset" and "sunrise" for is for 121 ops; we always had to be off the ground before sunset when departing from runways with no lights.
How can we tell if the sun is 6 degrees below the horizon anyhow? It's below the horizon, so we can't see it, lol.

 

[A Squared]

When is the official night used for anything?

91.151 night VFR fuel reserves

91.155 VFR minima for night flight

91.205 required equipment for night flight

121.590 runway lights for pax operations

just for example

 

[UndauntedFlyer]

What is really strange about all these different uses of the night definitions is that a person can be not qualified for night landings with passenges and still land 59 min past sunset when it would be pitch dark and as far as the FAR's are concerned: That was a day landing. Go figure out that one.

A Squared, thanks for your information on this too. Good work off the top of your head. .

 

[A Squared]

The only thing I use "sunset" and "sunrise" for is for 121 ops; we always had to be off the ground before sunset when departing from runways with no lights.

Do you have a source for that? I've heard that too, but haven't been able to find any support for it. I'm wondering if it's really an old wives tale or something dreamed up by some fed with too much time on his hands.

How can we tell if the sun is 6 degrees below the horizon anyhow?

By looking it up in the American AIr Almanac or the U.S. Naval observatory website.

 

[UndauntedFlyer]

Does anyone know if the American Air Almanac is still published? The one I have was printed in 1947...

 

[User546]

I was told by a flight instructor a long time ago that a good way to know civil twilight is when all the lights (street lights, house lights, signs, etc.) start coming on.

Don't know how accurate it is, but its always worked for me.

 

[CJCCapt]

Does anyone know if the American Air Almanac is still published? The one I have was printed in 1947...

Yes. Here is the link: http://aa.usno.navy.mil/publications/docs/NewAA1.htm (available on CD-ROM also on the website). Or use Midlifeflyer's link.

 

[CJCCapt]

Do you have a source for that? I've heard that too, but haven't been able to find any support for it. I'm wondering if it's really an old wives tale or something dreamed up by some fed with too much time on his hands.

14 CFR part 121.590(b)(2) states the requirement for "boundary or runway marker lights" for air carrier ops.

 

[nosehair]

I was told by a flight instructor a long time ago that a good way to know civil twilight is when all the lights (street lights, house lights, signs, etc.) start coming on.

Don't know how accurate it is, but its always worked for me.

BAM! DAM!...all these years....wasted time...sigh. . .

 

[A Squared]

14 CFR part 121.590(b)(2) states the requirement for "boundary or runway marker lights" for air carrier ops.

Right, I'm aware of that. In fact I mentioned it in a previous post. What I was asking about was a source for the comment that sunset to sunrise (rather than end of eveing twilight to begining of morning twilight) was the definition of night for that regulation. 121.590 only mentions "night" with no qualification. In that case I would assume that the part 1 definition of night is relevant, but I have heard on a number of occasions that it's sunset to sunrise. I've looked for something that clarifies that, but haven't found it. I would think that in absence of something official you can point to that specifies sunset to sunrise, the Part 1 definition would be used. Anyone seen something official?

 

[NoPax]

14 CFR part 121.590(b)(2) states the requirement for "boundary or runway marker lights" for air carrier ops.

OK...here it is....

Sec. 121.590

[Use of certificated land airports in the United States.]

[(a) Except as provided in paragraphs (b) or (c) of this section, or unless authorized by the Administrator under 49 U.S.C. 44706(c), no air carrier and no pilot being used by an air carrier may operate, in the conduct of a domestic type operation, flag type operation, or supplemental type operation, an airplane at a land airport in any State of the United States, the District of Columbia, or any territory or possession of the United States unless that airport is certificated under part 139 of this chapter. Further, after June 9, 2005 for Class I airports and after December 9, 2005 for Class II, III, and IV airports, when an air carrier and a pilot being used by the air carrier are required to operate at an airport certificated under part 139 of this chapter, the air carrier and the pilot may only operate at that airport if the airport is classified under part 139 to serve the type airplane to be operated and the type of operation to be conducted.
(b) (1) An air carrier and a pilot being used by the air carrier in the conduct of a domestic type operation, flag type operation, or supplemental type operation may designate and use as a required alternate airport for departure or destination an airport that is not certificated under part 139 of this chapter.
(2) Until December 9, 2005, an air carrier and a pilot being used by the air carrier in the conduct of domestic type operations and flag type operations, may operate an airplane designed for more than 9 but less than 31 passenger seats, at a land airport, in any State of the United States, the District of Columbia, or any territory or possession of the United States, that does not hold an airport operating certificate issued under part 139 of this chapter, and that serves small air carrier aircraft (as defined under "Air carrier aircraft" and "Class III airport" in Section. 139.5 of this Chapter.)

139.5
Air carrier aircraft means an aircraft that is being operated by an air carrier and is categorized as either a large air carrier aircraft if designed for at least 31 passenger seats or a small air carrier aircraft if designed for more than 9 passenger seats but less than 31 passenger seats, as determined by the aircraft type certificate issued by a competent civil aviation authority.

Class III airport means an airport certificated to serve scheduled operations of small air carrier aircraft. A Class III airport cannot serve scheduled or unscheduled large air carrier aircraft.

There's the reference to the 121 part...I'd need more references infront of me to determine the requirement. Doesn't appear to be there though. Jury's out.



Night has three legal definitions, as already pointed out, they are used to satisfy different parts of the regulations, and regulations being regulations don't always make complete sense.

UndauntedFlyer for all your types and experience, (aren't you also an examiner) you sure don't seem to know much! Makes me feel good about myself!

 

[Checks]

when it is Dark outside it is NIGHT!

 

[rettofly]

....a person can be not qualified for night landings with passenges and still land 59 min past sunset when it would be pitch dark and as far as the FAR's are concerned: That was a day landing. Go figure out that one.

That makes as much sense as the 8-hour alcohol rule. You are in violation if you have a sip of any adult beverage at 7:59 hrs before flying, even though your BAC is 0.00, but you can get hammered and fly with a 0.02 BAC as long as the last drop crossed your lips at least 8:00 hours before you fly.

 

[User546]

Just leave it up to the FAA to take something as f**king simple as NIGHT TIME and make it completely confusing.